Chad Billingsley cruised into the fifth inning with a two-run lead and retired the first two batters. Then, he threw a first-pitch fastball that hit Cincinnati rookie shortstop Zack Cozart in the helmet.
Cozart left with a concussion and Billingsley wasn't quite the same after that.
Rookies Devin Mesoraco and Todd Frazier each drove in three runs and the Reds rallied past the Dodgers 8-2 Monday night.
Cozart singled his first two times up before being struck by Billingsley. Cozart held his head with both hands while lying on his stomach for several anxious moments before walking off under his own power.
Pitching coach Rick Honeycutt came out to settle down Billingsley after the scary incident, and he retired the slumping Drew Stubbs for the third out.
"We just thought it was a good time to take a moment, step back and absorb the whole thing and gather his thoughts so that he could keep pitching well," Honeycutt said. "He was throwing the ball extremely well to that point, but there was just a change of momentum there, and unfortunately, he didn't escape that sixth inning."
After the game, Cozart said he was doing better.
"I think it just got away from him. I don't even really remember, to be honest," Cozart said. "I just remember hearing a pretty loud bang then I had some ringing in my ears, and that's why I was on the ground holding my ears."
"I've been hit before a couple of years ago in the minor leagues, and it was worse then because it got me under the helmet. But this one was scary because it was so loud when it hit the helmet," he said. "That's why we wear helmets. The doc just said to monitor it throughout the night. I think everything should be OK. I feel fine. I feel a lot better than I thought I was going to be."
Homer Bailey and the NL Central leaders sent the Dodgers to their 12th loss in 14 games.
Cincinnati played without All-Star first baseman Joey Votto, who has inflammation in his left knee, and third baseman Scott Rolen, who was scratched after leaving Sunday's game at San Francisco because of back spasms.
Bailey (6-6) allowed two runs and five hits in eight innings, striking out seven and walking one.
Billingsley (4-8) lost his fourth straight start, giving up three runs and six hits in six innings with eight strikeouts and no walks. The right-hander is 0-4 with a 4.70 ERA in his last eight outings at Dodger Stadium.
Brandon Phillips doubled and scored Cincinnati's first run on Frazier's broken-bat single in the sixth. With two outs, Mesoraco delivered a two-run double down the left-field line to put the Reds ahead 3-2.
Cincinnati tacked on two more in the eighth against Todd Coffey with Frazier's RBI triple and Mesoraco's run-scoring single.
Jerry Hairston Jr. sent a drive into the Dodgers' bullpen in left field in the first inning — only the second home run by Los Angeles in its last 18 games.
Luis Cruz, whose contract was selected from Triple-A Albuquerque on Monday, made it 2-0 in the second with a sacrifice fly. Cruz started at shortstop and was 0 for 2 in his Dodgers debut after stints with Pittsburgh and Milwaukee. He signed with Los Angeles as a free agent in November.
Dodgers shortstop and leadoff hitter Dee Gordon, whose two throwing errors in back-to-back plays led to a pair of unearned runs in the Dodgers' 8-3 win over the New York Mets on Sunday night, was on the bench. He leads the majors with 28 stolen bases, but is batting only .228.
NOTES: Dodgers CF Matt Kemp, who hasn't played since May 30 because of a recurring hamstring problem, will begin a minor league rehab assignment with Class A Rancho Cucamonga on Tuesday, hoping to return to the Dodgers' lineup on July 13. He also is planning on competing in the All-Star home run derby. ... LHP Ted Lilly, who has been sidelined since May 24 because of shoulder inflammation, was transferred to the 60-day disabled list to make room for Cruz on the 40-man roster. RHP Shawn Tolleson was optioned to Albuquerque. ... LHP Lenix Osuna, the 16-year-old son of former Dodgers reliever Antonio Osuna, was signed by the organization on Monday in his native Mexico.